General pathology · Cell injury, adaptation and death
Pigments in tissue: lipofuscin, hemosiderin, melanin, bilirubin, carbon !
- Lesion
Pigments are coloured substances that build up in tissue. Some come from outside, like coal dust; others the body makes, like iron or bilirubin.
Updated 2026-11-01
What it is
Pigments are coloured materials that accumulate in cells or tissues. Exogenous pigments come from outside (carbon, tattoo ink). Endogenous pigments are made in the body: lipofuscin (wear and tear), melanin, hemosiderin (stored iron) and bilirubin. Recognising the pigment and its stain points to the cause: aging, bleeding, iron overload or liver disease.
Key facts
- A bruise changes colour as hemoglobin becomes biliverdin (green), bilirubin (yellow) and hemosiderin (golden brown).
- Hemosiderosis from repeated transfusions or chronic hemolysis first loads macrophages; hemochromatosis loads parenchymal cells.
- Heart-failure cells are alveolar macrophages full of hemosiderin from congested lungs.
- Dubin-Johnson syndrome gives the liver a black colour from a melanin-like pigment.
Pigments to recognise
| Pigment | Origin | Appearance and stain | Meaning |
|---|---|---|---|
| Carbon | Exogenous: inhaled soot and coal dust | Black granules in macrophages | Urban exposure; coal worker’s pneumoconiosis |
| Lipofuscin | Endogenous: peroxidized membrane lipids | Fine golden-brown perinuclear granules | Aging, atrophy (brown atrophy) |
| Melanin | Endogenous: tyrosine in melanocytes | Brown-black; Fontana-Masson stain | Skin colour, nevi, melanoma; absent in albinism; ochronosis is a related dark pigment in alkaptonuria |
| Hemosiderin | Endogenous: excess iron stored as ferritin aggregates | Golden-brown granules; Prussian blue positive | Bruise, heart-failure cells in lung, hemosiderosis, hemochromatosis |
| Bilirubin | Endogenous: heme breakdown | Yellow-green; bile plugs in canaliculi | Jaundice; kernicterus in newborns |
Clinical notes
- Patients with thalassemia or sickle cell disease on chronic transfusions need iron monitoring and chelation to prevent organ damage.
- Hereditary hemochromatosis is treated by regular phlebotomy, which removes iron before organs are damaged.
Test yourself
Think of the answer, then tap the question to see it.
Which stain identifies hemosiderin?
Prussian blue (Perls), which colours iron blue.
What is lipofuscin and what does it indicate?
A golden-brown pigment of lipid peroxidation products in lysosomes; it indicates aging or atrophy and is not harmful in itself.
What are heart-failure cells?
Alveolar macrophages filled with hemosiderin from red cells that leaked into congested lungs.
Related
- Intracellular accumulations: cholesterol, proteins, hyaline, glycogen
- Atrophy
- Cellular aging: telomeres, DNA damage, senescence and proteostasis
- Oxidative stress and free-radical injury
- Air pollution and occupational exposures
- Special stains in diagnosis: Congo red, Prussian blue, PAS, Ziehl–Neelsen, Gram
Related conditions
- Hereditary hemochromatosis
- Pneumoconioses (silicosis, asbestosis, coal workers' pneumoconiosis)
- Thalassemias (α and β)
- Sickle cell disease
- Heart failure
- Neonatal jaundice
- Crigler-Najjar syndrome
- Dubin-Johnson syndrome
- Alkaptonuria
- Oculocutaneous albinism
- Melasma
Elsewhere in DurgiPedia
- Bilirubin
- Heme breakdown and bilirubin
- Iron metabolism
- Body iron balance
- Keratinocytes, melanocytes, Langerhans and Merkel cells
- Microscopy and stains: H&E, PAS, trichrome, silver, immunohistochemistry
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Coal worker's pneumoconiosis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2024); Hemochromatosis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2024); Jaundice | Icterus | MedlinePlus (MedlinePlus, US National Library of Medicine, 2024).
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Representative model, for educational purposes only.